bool checkIfPangram(char* sentence) {
	int exist[26] = { 0 };
	int i = 0;

	while (*sentence) {
		exist[*sentence - 'a'] = 1;
		sentence++;
	}
	for (i = 0; i < 26; i++) {
		if (exist[i] == 0)
			return false;
	}
	return true;
}